s212 rear air suspension - confused !

[frubpato]

This ****** car is messing with me - sometimes it will keep its ass in the air for 2weeks plus - even when left in an airport car park , and at other times over night or even within a couple of hours it is right down on its hunkers.
i guess that would suggest its not a airbag leak or even the pipes as that would be constant , could it be a battery issue where the electronic level sensors to the distribution block require a certain voltage to keep things level?
any other ideas - btw the codes for "level sensor" signal outside permitted range is generated when the car goes down but otherwise everything is fine - the right left heights are 4 mm out but that could easily be due to me being in the car when the codes are being read

 

[malcolm E53 AMG]

This is becoming a regular fault on the forum (do a search for rear airbags fault) the rear airbags are starting to split and whether or not they deflate largely depends on how the car is parked. My advice would be to replace them both assuming everything else checks out ok

 

[Blobcat]

This is becoming a regular fault on the forum (do a search for rear airbags fault) the rear airbags are starting to split and whether or not they deflate largely depends on how the car is parked. My advice would be to replace them both assuming everything else checks out ok

And before the pump burns out from over use...

 

[frubpato]

thanks for that - i had done quite a trawl of the posts and have the thread with the pictures and instructions - just wanted to explore why they some times stay up and sometimes dont - thanks @malcolm210 you have answered that for me

 

[Kersidan]

As above ^ air bags leaks can be inconsistent. I replaced mine with ones from Aerosus, very good quality and sorted my intermittent sagging rear end!

 

[frubpato]

Well apart from unseating the airbags it went exactly as the forum posts suggested, until.......
Time to power up the system and nothing happens. Checking for any fault codes , nothing but when I looked at actual values it tells me that the pump is locked due to limp mode activated. I can’t see any limp mode codes - any suggestions. Clearly I can’t drive it anywhere with no air in the bags

 

[malcolm E53 AMG]

Could be the pump fuse or relay? The relay is situated in the rear cargo area just pull down the passenger side panel and there is a cutout towards the bottom of the trim, always a good idea to replace the relay when you do major work on the airmatic system.

 

[frubpato]

Thanks @malcolm210 - relay changed -although the original seemed Ok and the compressor is unlocked and the car is level . Good man ! What with a new inlet manifold last week and the airbags this week Helga has had some expensive pampering !

 

[malcolm E53 AMG]

Thanks @malcolm210 - relay changed -although the original seemed Ok and the compressor is unlocked and the car is level . Good man ! What with a new inlet manifold last week and the airbags this week Helga has had some expensive pampering !

Glad you got it sorted!

I always keep a spare relay in the car (they are as cheap as chips to buy)

 

[frubpato]

So , now the weather looks set fair for a couple of days I need to do the near side airbag. While there were really good instructions for taking off the shock for the off side , how on earth do I remove the interior trim panel on the near side?

 

[frubpato]

just to close this off - the near side trim panel has a yellow push clip just underneath where the parcel shelf attaches . It neds a small prybar to release it and it comes off with a pop but seems to survive. After that the procedure is the same as the offside - taking the shock off completely makes getting the spring out easy - the only thing i would add is that it took 24hours of being doused in wd40 to release 9 years of baked on crud and allow the bottom of the spring to be thumped out - a lump hammer and drift (or 1/2inch extension in my case) does the job but you do need the car a decent height off the ground to give you room to use the hammer
once again thanks to @malcolm210 for his online support during this

 

[EmilysDad]

...
it took 24hours of being doused in wd40 to release 9 years of baked on crud and allow the bottom of the spring to be thumped out ...

Glad you're sorted, but there are far better penetrating fluids than WD40 eg Plusgas. WD40 is a water disperser